Investigate the vibrational modes of double helical DNA. Study such modes for instabilities (soft modes) which indicate onset of conformation change. Do such analysis for specific nucleotide sequences. Analyze other mechanisms in which knowledge of vibrational modes is important. Experimentally measure the f.i.r. spectrum for DNA and RNA polymers as well as crystalized components such as bases nucleosides and nucleotides from 20 to 500 cm minus 1. Use experimental results to refine force constant models. Use refined force constants to improve vibrational mode models.